Nerds serve an often vital role in cinema. In an action movie theyll be the people a grizzled cop will go see to decode some information or the awkward best friend in a teen comedy. They can come in a few different varieties. In most cases, glasses are a must. Theyll often have a geeky t-shirt, showing off their favourite comic character or movie and probably have a few spots or zits if a filmmaker really wants to hammer home their nerdiness. Oh, and their hangout will have lots of posters on the wall, with maybe a few toys or empty pizza boxes thrown in for good measure. And in most cases, theyre not the main character. So when nerds are promoted to a leading role, this can be something of a casting problem. Studios dont want to hire a geeky looking actor to front their multimillion dollar movie, so they have to find someone with star power. But how does somebody with movie star looks and charisma convince an audience that theyre really into computers and Star Wars? A privileged few, like Joseph Gordon-Levitt or Zooey Deschanel, can walk that fine line between being convincingly dorky while still having that movie star X-factor. But for most actors, like those mentioned on this countdown, it just goes to show that putting glasses on someone doesnt instantly turn them in a computer genius or math whizz. Its fun to watch them try though.